ArcGIS Pro 3.4 API Reference Guide
ArcGIS.Core.Data Namespace / RelationshipClass Class
Members Example Version

RelationshipClass Class
Represents an association between two tables in a geodatabase.
Object Model
RelationshipClass ClassRelationship ClassDatastore ClassRelationshipClassDefinition ClassFeatureDataset Class
Syntax
public class RelationshipClass : Dataset, System.IDisposable  
Remarks
The primary difference between a RelationshipClass and AttributedRelationshipClass is that a RelationshipClass does not have an intermediate table.
Example
Joining a file geodatabase feature class to an Oracle database query layer feature class with a virtual relationship class
public async Task JoiningFileGeodatabaseFeatureClassToOracleQueryLayer()
{
    await ArcGIS.Desktop.Framework.Threading.Tasks.QueuedTask.Run(() =>
    {
        using (Geodatabase geodatabase = new Geodatabase(new FileGeodatabaseConnectionPath(new Uri("C:\\Data\\LocalGovernment.gdb"))))
        using (Database database = new Database(new DatabaseConnectionProperties(EnterpriseDatabaseType.Oracle)
        {
            AuthenticationMode = AuthenticationMode.DBMS,
            Instance = "instance",
            User = "user",
            Password = "password",
            Database = "database"
        }))

        using (FeatureClass leftFeatureClass = geodatabase.OpenDataset<FeatureClass>("Hospital"))
        using (Table rightTable = database.OpenTable(database.GetQueryDescription("FacilitySite")))
        {
            Field originPrimaryKey = leftFeatureClass.GetDefinition().GetFields().FirstOrDefault(field => field.Name.Equals("facilityId"));
            Field destinationForeignKey = rightTable.GetDefinition().GetFields().FirstOrDefault(field => field.Name.Equals("hospitalID"));

            VirtualRelationshipClassDescription description = new VirtualRelationshipClassDescription(
        originPrimaryKey, destinationForeignKey, RelationshipCardinality.OneToOne);

            using (RelationshipClass relationshipClass = leftFeatureClass.RelateTo(rightTable, description))
            {
                JoinDescription joinDescription = new JoinDescription(relationshipClass)
                {
                    JoinDirection = JoinDirection.Forward,
                    JoinType = JoinType.LeftOuterJoin
                };

                Join join = new Join(joinDescription);

                using (Table joinedTable = join.GetJoinedTable())
                {
                    // Perform operation on joined table.
                }
            }
        }
    });
}
Inheritance Hierarchy

System.Object
   ArcGIS.Core.CoreObjectsBase
      ArcGIS.Core.Data.Dataset
         ArcGIS.Core.Data.RelationshipClass
            ArcGIS.Core.Data.AttributedRelationshipClass

Requirements

Target Platforms: Windows 11, Windows 10

ArcGIS Pro version: 3 or higher.
See Also